On Mar 21, 8:00 pm, Colin Mollenhour <[EMAIL PROTECTED]>
wrote:
> What you are doing is the equivalent of
> Commentable.prototype.comments = []
> which creates a sort of shared variable among all instances of that object. I
> guess the reason object_ID isn't being overwritten is because when you use
> this.object_ID = ...;
> you are overwriting the shared variable with a local variable for that
> instance. However,
> this.comments.push(...);
> is referencing the shared variable. So, for properties of an instance, always
> use
> this.someProperty = ...;
>
> This will work:
>
> Commentable.prototype = {
> initialize: function(elmid) {
> this.object_ID = $(elmid);
> this.comments = [];
> this.eventOnClick = this.newComment.bindAsEventListener(this);
> Event.observe(elmid, 'click', this.eventOnClick, false);
> // save the commentable object away.
> Commentables.register(this);
> },
> ...
>
> }
>
> Colin
>
> stephen O'D wrote:
> > I am trying to implement something in the style of Draggables, where I
> > can specify an HTML element that I want to place comments against by
> > clicking on the element. So I have copied the style of Draggables and
> > created the following:
>
> > <html>
>
> > <head>
> > <script src="javascript/prototype.js" type="text/javascript"></script>
> > <script src="javascript/scriptaculous.js" type="text/javascript"></
> > script>
>
> > <script type="text/javascript">
>
> > var Commentables = {
> > commentable: [],
>
> > register: function(commentable) {
> > this.commentable.push(commentable);
> > }
>
> > }
>
> > var Commentable = Class.create();
>
> > Commentable.prototype = {
> > comments: [],
> > object_ID: '',
>
> > initialize: function(elmid) {
> > this.object_ID = $(elmid);
> > this.eventOnClick = this.newComment.bindAsEventListener(this);
> > Event.observe(elmid, 'click', this.eventOnClick, false);
> > // save the commentable object away.
> > Commentables.register(this);
> > },
>
> > newComment: function(event) {
> > alert('i have been clicked: '+this.object_ID.id);
> > this.comments.push('a comment on '+this.object_ID.id);
> > this.showComments();
> > },
>
> > showComments: function() {
> > this.comments.each( function(c) { alert(c) } )
> > }
> > }
>
> > Event.observe(window, 'load', page_loaded, false);
>
> > function page_loaded(evt) {
> > var one = new Commentable('firstone');
> > var two = new Commentable('secondone');
> > }
>
> > </script>
>
> > </head>
>
> > <body>
> > <div id="firstone">some text just to give the div a width</div>
> > <div id="secondone">more text here just for padding.</div>
> > </body>
> > </html>
>
> > So basically I have two clickable DIVs, and when you click on each, it
> > displays an alert telling you which was clicked by calling newComment,
> > and then displays all the comments saved against that DIV.
>
> > It always displays the correct Object_ID, however when I call
> > showComments, it displays an altert for every comment on ALL
> > commentable objects.
>
> > ie click on firstone:
>
> > alert('i have been clicked firstone');
> > alert('a comment on firstone');
>
> > then click on secondone (without refreshing the page):
>
> > alert('i have been clicked secondone');
> > alert('a comment on firstone'); // ****** why is this one coming
> > out too??
> > alert('a comment on secondone');
>
> > I reckon my understanding of how javascript works going wrong here,
> > but why do the contents on the comments array for both object get
> > shown when I thought that only the contents of the one associated with
> > the DIV I click on should? Have I created my objects wrong?
>
> > Any help is much appreciated as I am baffled about this one!
>
> > Thanks,
>
> > Stephen.
Ah! So the way I was doing it was sort of creating what would be
known as Class variables in Ruby speak - variables that are shared by
all instance of the class. Makes sense now.
Thanks for the help.
Stephen.
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